Fluid cooled superheater construction



May 14, 1935. c. s. TURNER FLUIJDI COOLED SUPERHEATER CONSTRUCTION I Filed May 2; 1931 2 Sheets-Sheet l M A W mfg/Qu che 2 INVENTOR m-Jas 8. 720723)" ATTORNEYS c. s. TURNER 2,001,556

FLUID COOLED SUPERHEATER CONSTRUCTION May 14, 1935.

Filed May 2, 193l 2 Sheets-Sheet 2 ATTO R N EYS Patented May 14, 1935 PATENT OFFICE FLUID COOLED SUPERHEATER I CONSTRUCTION Charles S. Turner, Detroit, Mich. Application May 2, 1931, Serial No., 534,490

7 Claims.

This invention relates to superheater constructions, and has for its object an improved organization of parts adapted especially for installation in locomotive boilers, though of equal utility in many stationary constructions. It has to do particularly with the protection of the superheater tube walls from impairment due to their exposure to the high heat conditions prevailing within the furnace chamber, and resultantly the confinement of the temperature of the steam within proper bounds. The invention herein disclosed centers particularly about those types of superheater installations which might be described as pendent or projecting, in that each of the several superheater tubes of an installation projects either vertically or horizontally into the heating space, being connected at one end with its manifold or header, while the outer or exposed end is closed; but each contains within it divisional Walls or fluid conduits which selectively guide the course of both the steam flow and a column of cooling water within the shell-enclosed space, whose inletsandoutlets are all at one end, and which may be compared cross-sectionally to a bay or elongated pocket, the entranceof which represents the connection with the superheater headers.

In the drawings:

Figure 1 is a sectional elevational view, show ing many already-known parts of a water tube boiler installation, with one form of my improved superheater element here disclosed installed with relation thereto.

Figure 2 is a similar sectional elevational view of what might be termed the horizontal type of my superheater installation positioned within a locomotive or fire tubular type boiler.

Figure 3 is a partly sectional elevational view of a superheater header with depending tubes shown in relation to some such source of heat as a fire bed within a furnace; this being taken from a direction perpendicular to that of Figure l, and designed to bring out particularly the plural and spaced relation of each end-closed superheater tube to its neighbors and to the adjacent boiler tube bank and furnace parts.

Figure 4 is a sectional elevational View of a single vertical superheater unit of the type herein dealt with, on a very much enlarged scale from the showing in Figure 1. r I Figure 5 is a cross-sectional view on a larger scale of the preferred form of superheater tube unit shown in Figure 4, and as it is preferably employed for such vertical installations as are illustrated in Figures 1 and the line 5-5 ofFigure4. i 1

Figure 6 is a longitudinal cross-sectional view on a larger scale of apreferred form of superheater tube employed in the horizontal installa- 5 tion suggested in Figure 2. v 1

Figure 7 is a large scale sectional view of such a tube, similar to Figure 5, beingtaken along the line 1-1 of Figure 6. v 'Figure 8 is a sectional view taken substantially on the line 8-8 of'Figure 6 and looking in the direction of the arrows, on a somewhat smaller scale and suggestive of a slightly modified form of connecting construction between the tube proper and the superheater manifold, wherein, by the use of a dividing diaphragm, the watercirculatory tubes of one side and the steam spaces about them are-separated, forming a second or outflow series located in the other side or half of the shell shown. 20 Figure 9 is a sectional and elevational view of the end of one form of superheater tube, taken along the line 99 of Figure 4 and looking in the 3, being taken along direction of the arrows there shown.

Referring first to what I have styled the vertical type of superheater element herein disclosed, the parts l2 in Figure 1 represent ordinary furnace walls and I3 the fuel bed or burning level. Across the upper portion of the furnace space extend the ordinary boiler tubes l 4, which connect the drums l5 and I6 and which are in turn connected by means of the piping series l8 and I9 with the third drum [1. At 20 is shown a water supply pipe leading from a suitable water supply source such as the lower drum I5 and the outlet therefor is shown at 2|, while at 22 is shown the valve and manifold controlling water supply to the pendent or vertically positioned superheater element 23 which forms the subject matter of one form of the invention here to be disclosed, ordinarily steam being admitted thereto through the inlet 24, and its egress therefrom taking place through its outlet or header 25. Most of the elements thus far mentioned are now well-known and in common use, and mention of them is made primarily for the purpose of enabling a clear understanding of the functioning of the superheater element 23 relatively thereto, the interior details and connections of one form thereof, brought out in Figures 4 and 5 particularly being new to be described. 1

The spaced relation of these several pendent superheater tubes 23 across the front of the boiler space is further illustrated in Figure 3, and it will-be noted, both from an examination of that furnace chamber, which to a degree cuts down the amount of heat which would otherwise impinge upon, and make its way through, the'wall 12 In the conventional form of furnace and boiler sheet shown, the oblique positioning of the wall or baille 1 2 enables the pendent superheater element 23 to project straight downwardly into the furnace as shown, the headers beingarranged above the bafile. Since, however, the protection of the header from undue heat requires :in any event that it be located outsidelthe furnace chamber, if some other contouring of the walls thereof *were used,it might be necessary to bend the length of each superheatertube, .so that while generally depending intoithe furnace chamber, its header would .be protectedlyioutside thereof, as for example at one side; a f

Each'of the superheater tubes 23 is provided with a roundedor'close'd end,'as-23 so that whatever steam or water is introduced into themcan only emerge therefrom, after its circulatory phase hasbeen completed, through the same end of the superheater assembly as that through which it entered, namely, the opposite end from the exposed pendent portion 23, and the guidedcirculation of both steam and water columns therewithin must be and is effected by the selective positioningwithin it of partitions or walls, in reality the various tubes orpipes which will be described, and which infthe aggregate amount to a plurality of fluid-Aguiding longitudinal chambers, each of which is connected with either the steam system" or the water system to the exclusion of the-other, the'steam inlet and outlet respectively being shown at 24 and 25 in Figure 1, while the valve-controlled water connections are indicated "at 2| and 22 therein, It is obvious that the most exposed part of each superheater tube, namely its closed end 23 must have'this watercooling protection most *of all, and to that end, in both of the'forms herein disclosed, my invention centers about effecting the intimate relation of the water column with this endaccordingly.

Figures 4 and 5, sectionally illustrative of this vertical or pendent type ofsuperheater tube assembly should be studied in quite close association with Figures 1 and 3, particularly the former, since it must be borne in mind that the steam supply entering the space enclosed by the superheater tube 23 through theintermediate pipe26, whose end is open, encounters at the far end of the superheater tube 23 the solid center of the spider 21, and finds its only possible egress .to be through the .annularly disposedspaces .28, between the pipe 26 and 'the peripherally surrounding cooling fluid pipes 29, whose outer peripheral points touch, indeed'are preferablyattached as by welding 30, to the inner surface of the end-closed tube or shell 23. v

The water brother cooling fluid, onthe other hand, enter past the inlet 22, proceeds-through therelatively smaller central pipe -3 I "to the chamber :32 at the closed lower end of the superheater tube 23, from which its only egress is upwardly through the several peripherally arranged passages 29 and out at the upper end through the part 2|. The weight of the descending and relatively cool water column within the pipe 3| being greater than the thermally rising and more or less bubble-filled water passing upward through the passages 28 isgenerally sufficient to set up such .a natural convection v.or self-induced circulation, quite 'aside from what pressure there may be in the cooling fluid supply systemwhichv is acting upon the water entering through the inlet 22, since the exposure of the outside welded .wallilines 311 of each cooling pipe to the heat from the furnace chamber, through the walls of the outer tube 23, acts to rapidly raise their temperature.

Between these several inlet water pipes 29,

howevenare located the several spaces 28 to "which heat units pass through the walls of the outer tube 28,.for thermal'action upon the steam within the-spaces or chambers 28 and'upon the outfiowing columns of fluid to be acted upon.

Most of the operative principlesTinvolved in the construction and use of the. verticaltor'pendent type of superheater tube vthusfar discussedicarry over into the horizontal or so-called locomotive type, illustrated particularly in .Figures 6, 37:, and 8, inthat the requirements for theadequate protection of the header connections from undue heat remain, together with the general requirement that the outer or heat-'exposedendof the superheater tube be closed, and that ingress and egress both of "steam and of the cooling medium be at the header end of theltube. As brought out in Figure 2, the horizontal "tube 40 is 'connected, as at 4 I, witha steam source, the flow from which proceeds through thetube 42 spacedly lengthwise of the'exposed or superheater tube 40. Theouter end of this tube 42 is spaced from the closed or pocketed end of the tube 40, so that the steam emerges therefrom into the chamber 43. Arranged ,innspaced relation about the steam tube 42 :are 'a series of water-cooling tubes, of which six are shown cross-sectionally inFigures '7 and 8. These extendlengthwiseof the tube-and'are arranged in two series, three of these tubes, as

a, b, 0, being designed for the outward flow, that is toward the-outer end of the superheater'tube, of the cooling water which enters through the inlet, while the remaining three, as d, e, and f, form U-shaped continuations of the respective tubes a, b, 0, being positioned on the other-side of the dia'metrical diaphragm 45, aredesig'ned to care'for the return flow of the coolingm'e'diumtoward the water outlet -46. These pipes are preferably welded along their lines of union to the inner surface of the superheater tube wall 40, as indicated-at 48, but they are in spaced relation thereabout,leaving alternated spaoes,as 41, through which the steam introduced lengthwise of the tube 40 through the tube and thence discharged in the chamber 43 may make its way backward toward the steam outlet 49. Thusa continuous cooling, fluid current is maintained through the passages thus peripherally disposed within the shell 40 and about the outside of the steam pipe 42, while on its return travel the steam as it passes through thelseveral vacant spaces 41 is exposed to the maximum of superheating influence which makes its way through those wall portions of the superheater tube 40 which bound the outside of the several spaces 41. It will be noted that the three water inlet channels, :a,':b., and c, are located on the under side of the superheater unit as positioned in the furnace space, whereas the three outlet tubes d, e, and f are located in thetop side, thus giving the cooling fluid stream the benefit of whatever acceleration may result from the outgoing andmore or less bubble-filled cooling water having a tendency to rise from the level of the three lower cooling tubes a, b, and c to that of the three upper tubes d, e, and Of course any desired number of cooling tubes, more or less than those herein illustrated, could be employed, depending upon the operative conditions to be dealt with. As brought out by comparison of the cross-sectional Figures 6 and 8, the steam entering the centrally located steam inlet pipe 42, from the steam source connection 4|, passes through the apertured diaphragm 45 which separates the inlet series of water-cooling tubes, a, b, and c from the outlet series d, 'e, and 1, so that the water flowage pipes are kept wholly to themselves, leaving all of the interspersed steam outlet spaces 41 clear for the steam outflow after it has been delivered into the chamber 43 through the inlet pipe 42.

The two forms of end-closed superheater tube illustrated herein and which throughout this specification I have referred to as the vertical and the horizontal types respectively are mutually interchangeable provided forced circulation of the cooling fluid column can be relied upon; but if the variances in temperature between the relatively cool inflowing column and the rapidly rising-temperatured outflow column be relied upon alone for starting this cooling fluid circulation, my experience has been that while the so-called horizontal type can, even under these conditions, be substituted for the vertical type, the reverse is not true, that is to say, the so-called vertical type could not be substituted for the horizontal type.

What I claim is:

l. A fluid-cooled superheater tube unit, having, in combination with an outer shell adapted for inlet and outlet connection at the same end with an external steam supply source, the other end of said shell being closed, cooling fluid conducting pipes arranged within said outer shell in position to conductively receive heat units impartedto certain external surface portions thereof from an outside source and adapted in turn to modifyingly transmit the normally lower temperature of their contents to certain of the spaces within said outer shell not occupied by such pipes, and an interiorly positioned steam pipe for introducing a supply of steam adjacent the closed end of said outer shell, whence it is adapted to emerge, while subjected to the thermal influences described, through the available lengthwise passages therein.

2. In a superheater construction, in combination with a common header, a plurality of fluidcooled superheater tube units terminally connected therewith in spaced relation to one another, each of said units comprising an outer shell closed at its end remote from its point of connection with the header, an interior tube spacedly surrounded by said outer shell, and a plurality of fluid-conducting tubes located within said outer shell and surroundingly of said interior tube, each of said elements being separately connected at its inner end with external fluid supply and outlet elements, whereby the fluid columns admitted to the contents of the several fluidconducting passages are subjected to heat-interchanging influence with the contents of those adjacent, thereby regulatably holding within predetermined limits the heating influence exerted upon the outer shell of the several superheater tubes. 1

3. A fluid-cooled superheater tube unit, comprising a pair of coaxially disposed tubes arranged one within the other in spaced relation, the outer end of the larger one of said tubes being closed, means for conducting steam through the inner to a point adjacent the closed end of the outer tube and for returning the same through said outer tube, and a series of fluid-cooling outflow and return tubes positioned between the spaced walls of said coaxially disposed tubes for modifyingly influencing the temperature thereof and of steam therewithin, a cooling fluid supply source connected to the outflow and take oif means which are in turn connected to the return tubes.

' 4. In a fluid cooled superheater, a conduit, a casing longitudinally surrounding the conduit and radially spaced therefrom to form a chamber, and a plurality of cooling fluid ducts circumferentially spaced within said chamber to form, with said casing and conduit, a plurality of passages.

5. A superheater unit comprising a casing, a plurality of tubes within said casing, at least one of said tubes being connected to a steam inlet, others of said tubes being connected to a fluid cooling system and forming a cooling fluid circulating system spaced circumferentially of said inlet, and means integrally connecting the tubes of said circulating system to the casing.

6. In a heater unit, in combination, a pair of substantially concentric spaced pipes forming an annular chamber therebetween, a plurality of independently walled conduits extending longitudinally within said chamber and having wall portions abutting said pipes, said conduits being circumferentially spaced from each other around said chamber and forming a plurality of spaced independent passageways between said conduits and within said chamber, whereby fluid may be conducted through said annular chamber both inside and outside of said conduits, integral heat bridging means between said conduits and. at least one of said pipes, an inner one of said concentric pipes being connected to certain only of the channels formed by said conduits and the passageways therebetween, and separate fluid supply means connected one to said inner pipe and passageways and another to said conduits.

7. In a .heater unit, in combination, a pair of substantially concentric spaced pipes forming an annular chamber therebetween, a plurality of independently walled conduits extending longitudinally within said chamber and having wall portions abutting said pipes, said conduits being circumferentially spaced from each other around said chamber and forming a plurality of spaced independent passageways between said conduits and within said chamber, whereby fluid may be conducted through said annular chamber both inside and outside said conduits, integral heat bridging means between said conduits and the outer of said pipes, a cooling flowage system having inflow and outflow connections connected to said conduits at the same end of the unit, and another cooling fluid system having inflow and outflow connections at the same end of the unit connected to one of said concentric pipes and to the passageways formed by the spaces between said conduits.

CHARLES S. TURNER. 

